i especially like it how slick realizes, like many, many people before him, visting IKEA mostly reminds you of how much crap you already have in your own home.

It's a reference to Fight Club. First you see "New Jack Cartoonist", where Jack is the main character in the movie. The Ghetto IKEA is a twist of the moment when Jack realises that "Like everyone else, I had become a slave to the IKEA nesting instinct." and moves in an abandoned ghetto-like mansion. There, his place looks just like in the "Ghetto IKEA" mall, so that's why you see Slick saying "I already got most of this stuff". It's a very subtle strip.

actually it's a reference to a difference movie, called NEW JACK CITY. very subtle, I know.

Evidence #1
From wikipedia:
Ishida admits that Slick's appearance is based on Calvin from Bill Watterson's Calvin and Hobbes; he has the same spiky blond hair and diminutive stature, but he is always wearing shades.